Jolt-squeeze molding machine

ABSTRACT

A foundry molding machine providing both an anvil jolt and a shockless jolt during squeeze which includes a ram projecting through the squeeze piston, such ram serving as a stationary stem cooperating with the table to obtain an anvil jolt and floating on the squeeze pressure during squeeze to obtain a shockless jolt.

United States Patent Abraham 1 Apr. 25, 1972 541 JOLT-SQUEEZE MOLDINGMACHINE 3,311,954 4/1967 Ellms ..164/196 3,205,542 9/1965 Miller et a1[72] Invent Edward Abraham Cleveland Ohm 3,461,947 8/1969 Abraham et a1...164/197 73 A Th Sh -Wi|l1 C Cl l 1 ssgnee eve FOREIGN PATENTS 0RAPPLICATIONS Great [21] Appl. No.: 860,381 Primary Examiner-J. SpencerOverholser Assistant Examiner-John E. Roethel A l' D 11 & R 52 us. 01..l64/195, 164/39 m Maky y emf [51] ..B22C15/30 57 ABSTRACT [58] FieldofSearch ..164/37-40, 195-197 A foundry molding machine providing bothan anvil jolt and a 56] References Cited shockless jolt during squeezewhich includes a ram projecting through the squeeze p1ston, such ramservlng as a stationary UNITED STATES PATENTS stem cooperating with thetable to obtain an anvil jolt and floating on the squeeze pressureduring squeeze to obtain a 2,619,695 12/1952 Young ..164/39 Xshocklessjolt 2,892,223 6/1959 Buhrer 3,111,730 11/1963 Ivarsson 164/196X 25 Claims, 6 Drawing Figures 1 A? v r 7s Z 84 I' I v 2 4e 1 n 14 5e ri 70 ii 55 I, a I I, i y 1| \.4, a; 54 i Q \1 v. 49 we & 1 57PATENTEDAPR 25 m2 SHEET 10F 4 rllll r C lllu'll Ill INVENTOR.

E DWARD D. ABRAHAM ATTQRN'EYS PATEHTEDAPR 25 I972 SHEET 2 [IF 4 IINVENTOR.

EDWARD D. ABRAHAM ATTORNEYS PATENTEDAPR25 I972 3, 658,1 l8 SHEET 3 {IF 4I7| I68 III I23 I26 I67 ATTORNEY S mvmon EDWARD 0. ABRAHAM 5.2g. 5

PATENTED 2 3,658,118

SHEET IIII 4 AM AMA AM ATTORNEYS JOLT-SQUEEZE MOLDING MACHINE Thisinvention relates generally as indicated to a joltsqueeze moldingmachine and more particularly to a simplified machine obtaining both ananvil jolt and a shockless jolt during squeeze providing molds ofuniform high density and hardness.

Many foundry people consider that optimum ramming of molding sand in theproduction of foundry molds can be obtained by jolting a mold in theconventional anvil jolt manner, i.e. wherein the shock is absorbed bythe base of the machine, and then squeezing the mold against a squeezehead while simultaneously applying a shockless jolt to the mold, or ajolt wherein the shock is not absorbed by the base of the machine. Thestandard anvil jolt apparently rams the deep pockets more effectivelythan can be done with shockless jolt, and a shockless jolt ramapparently helps to obtain maximum overall hardness ofthe mold.

It is accordingly a principal object of the present invention to obtaina simplified foundry molding machine providing both anvil jolt andshockless jolt during squeeze.

Another principal object is the provision of such machine which willobtain a more effective shockless jolt during squeeze.

A further important object is the provision of such machine which avoidsthe use of operating or compensating springs which may requirereplacement.

Another object is the provision of such machine having a ram whichprojects through the squeeze piston and into the squeeze chamber, thelatter thus serving as an air spring to rebound the ram against theunderside of the table.

A further object is the provision of such machine wherein the ram in itsinoperative position serves as a stationary stem cooperating with theunderside of the table to form an air chamber, alternate pressurizationand venting of which obtains an anvil jolt.

Still another object is the provision of such machine wherein thesqueeze pressure is varied in synchronism with the jolt to obtain a moreeffective overall hardness of the mold.

A yet further object is the provision of such machine wherein the ramduring shockless jolt projects into the squeeze chamber and pressure atthe top of the ram will drive it downwardly and when such pressure isvented, the squeeze pressure will cause the ram to rebound against theunderside of the table.

A still further object is to provide such a jolt molding machine havinga pivotally mounted pair of arms facilitating mold box turnover.

Other objects and advantages of the present invention will becomeapparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described, the followingdescription and the annexed drawings setting forth in detail certainillustrative embodiments of the invention, these being indicative,however, of but a few of the various ways in which the principles of theinvention may be employed.

In said annexed drawings:

FIG. 1 is a side elevation of a machine in accordance with the presentinvention;

FIG. 2 is a partial rear elevation of the machine of FIG. 1 illustratingthe mounting of the rollover arms and actuator;

FIG. 3 is a top plan view of such machine with the squeeze head removed;

FIG. 4 is an enlarged fragmentary vertical section taken in the plane ofFIG. 1 showing the table jolt and squeeze mechanism;

FIG. 5 is a vertical section of another slightly modified machine inaccordance with the present invention illustrating the table down, themold fllled and in position for anvil jolt; and

FIG. 6 is a view similar to FIG. 1 illustrating such machine with thetable up during squeeze and during shocklessjolt.

Referring first to FIGS. 1 through 3, it will be seen that theillustrated machine includes a generally upstanding frame 10,

to the forward lower end of which is secured table housing or base 11.The upper end of the frame 10 supports head 12 for horizontal swingingmovement on the axis of pin 13. Such head 12 supports a downwardlyprojecting squeeze board 14 which is generally vertically aligned in itsoperative position with table 15 supported for vertical movement in thetable housing or base 11. The squeeze head 14 can accordingly be swungout of the way to permit overhead filling of mold box 16 supported ontable 15 with molding sand.

The mold box 16 may be of the type including cope and drag flasks 17 and18, respectively, with a pattern or matchplate l9 therebetween. Suchflasks forming the mold box may include oppositely projecting trunnionsas indicated at 20 which are adapted to be engaged by cradles 21 on thedistal ends of arms 22 and 23, the proximal ends of such arms beingsecured by clamps 24 to the squared projecting ends of shaft 25journalled at 26 to the back of the upstanding frame 10.

To lift the mold box from the table 15, the arms 22 and 23 are pivotedupwardly to engage the mold box trunnions and such pivoting is obtainedby piston-cylinder assembly 28, the rod of which is connected at 29 toarm 30 secured to shaft 25. The blind end of such piston-cylinderassembly is pivotally connected at 31 to the frame 10. Extension of thepistoncylinder assembly 28 will thus pivot the arms 22 and 23 upwardlylifting the mold box until the trunnions obtain the position seengenerally at 32 so that the operator may then easily invert the moldbox.

Referring now additionally to FIG. 4, it will be seen that the table 15includes 21 depending cylindrical extension which fits within theupstanding cylindrical portion 41 of squeeze piston 42. The squeezepiston 42 includes a pair of piston rings 43 riding against the interiorcylindrical surface 44 of upstanding cylindrical portion 45 of the tablehousing or base 11. The top edge of the cylindrical portion 41 of thesqueeze piston 42 includes a lip 46 which overlies the top peripheraledge of the cylindrical extension 45 of the housing or base 11. Such lipincludes an annular flat surface 47 supporting the table 15 in itslowermost position.

A guide pin 49 mounted in the upstanding cylindrical portion 45 of thebase 11 projects into slot 50 in the upstanding cylindrical portion 41of the squeeze piston 42, such pin and slot maintaining the squeezepiston against rotation within its cylinder and also limiting itsvertical movement. A guide pin 51 mounted in the upstanding cylindricalportion 41 of the squeeze piston projects into slot 52 in the dependingcylindrical portion 40 of the table 15, such pin and slot connectionlikewise maintaining the table 15 against rotation and limiting itsvertical movement. In addition to the pin and slot connectionsaforesaid, the table 15 may be provided with a jolt guide pin 54extending through jolt guide bushing 55. Such guide bushing is mountedin extension 56 extending from the lip 46 of the upstanding cylindricalportion 41 of the squeeze piston 42 and also in knuckle 57 extendingfrom the upstanding cylindrical portion 45 ofthe base 11.

A rarn guide bushing 60 is mounted in a central aperture 61 in thesqueeze piston 42 and is secured in position by the fasteners 62 asindicated. An O-ring seal 63 is provided between the squeeze piston andsuch bushing. A sliding seal 64 is provided in such ram guide bushingriding against cylindrical downward extension 65 of jolt ram 66. Thelarger diameter portion of the jolt ram 66 slides within the cylindricalinner surface of the depending cylindrical portion 40 of the table 15. ATeflon or like piston ring 67 is provided as indicated between theappropriate sliding surfaces. It is noted that the axial extension ofthe sliding surfaces is minimized to avoid cocking problems.

Such sliding surfaces are also provided with lubricating passages asindicated at 68 and 69. The upper end of the jolt ram 66 is providedwith an upstanding cylindrical center projection 70 which in thelowermost position of the table has a slight clearance indicated at 71with the downwardly extending projection 72 on the underside of thetable. In such lowermost position of the table, the ram 66 through itslower cylindrical reduced diameter extension 65 is bottomed on the base11 as indicated at 73. The extension 65 ofthe jolt ram 66 thus projectsthrough the squeeze piston 42 into squeeze chamber 75 beneath suchpiston.

An intermediate chamber 76 is provided between the enlarged portion ofthe jolt ram and the top of the squeeze piston, such chamber alsounderlying the depending cylindrical extension 40 of the table 15. Suchchamber 76 is connected to atmosphere through passage 77 extendingthrough cylindrical extension 40.

A third chamber 78 is provided between the top of the ram 66 and theunderside of the table 15. The volume of the chambers 78, 76 and 75 aswell as the weight of the moving parts is carefully determined to obtainthe desired operation of the machine.

In operation, the table may support either the combined cope and dragflask mold box structure with the matchplate therebetween or a singleflask with a pattern plate supported on the table. After the mold boxhas been filled with sand, to obtain a conventional or anvil jolt, airat plant or line pressure (about 80 p.s.i.) enters the jolt chamber 78above the ram 66 through passage 79. The pressure in chamber 78 elevatesthe jolt table 15 until exhaust ports 80 are uncovered. Such exhaustports communicate with vertical grooves 81 in the exterior of thecylindrical depending extension 40 of the table 15, such groovescommunicating with ports 82 and vertical passages 83 in the upwardlyextending cylindrical portion 41 of the squeeze piston to exhaust toatmosphere through radially extending passages 84.

When such exhaust ports 80 are uncovered by vertical elevation of thetable, the table drops and strikes the annular top surface 47 of the lip46 of the squeeze piston 42 which is bottomed on the upstandingcylindrical portion 45 of the base 11. This anvil or conventional joltmay continue as desired to obtain suitable ramming of the sand withinthe flask. It will be appreciated that the extension 70 on the jolt ram66 may be slightly extended so that the anvil jolt is obtained on suchextension to provide a center strike through the ram bottomed on thebase 11 at 73.

During squeeze, air under pressure is admitted to the squeeze chamber 75and the squeeze piston 42 moves upwardly carrying with it the table 15.The squeeze board 14 telescopes within the top of the flask or mold boxpressing the sand against the pattern. The ram 66 also moves upwardlyand is held in contact with the underside of the jolt table closing theclearance 71. This movement ofthe ram is obtained by the squeezepressure acting on the underside of the ram extension 65 which isexposed to the squeeze pressure in squeeze chamber 75 beneath the piston42.

Jolt during squeeze is obtained by again introducing line pressure (80p.s.i.) through jolt line 79 into jolt chamber 78.

This pushes the ram 66 downwardly until air exhausts through the exhaustpassages 80, 81, 82, 83 and 84. When exhaust occurs, the squeezepressure in chamber 75 acting on the underside of the extension 65causes the ram to move upwardly striking the underside of the jolt tablein the center at the extension 72. Such shockless jolt during squeezemay continue until the mold has obtained its desired maximum overallhardness.

Even though the chamber 76 is vented to atmosphere through the passage77, downward movement of the ram 66 during such shockless jolt duringsqueeze will nonetheless compress the air in chamber 76 because of therestricted size of the vent passages and such compressed air will assistin driving the ram back against the underside of the table. lt is notedthat the area of the ram 66 exposed to the chamber 78 is considerablygreater than the area of the extension 65 exposed to the squeeze chamber75. Thus equal pressures in such chamber will cause the ram to movedownwardly. lt will, of course, be appreciated that such areas may varydepending on the pressures and pressure mediums employed.

After the mold is rammed, the table is lowered and the pat tern may bedrawn from the mold. When using the cope and drag flask with amatchplate therebetween, the piston-cylinder assembly 28 may now beextended elevating such mold box so that the operator may invert thesame and upon retraction of the piston-cylinder assembly 28 the box maythen be placed on the table inverted. The drag half of the mold box maynow be filled with sand and the operation repeated.

Referring now to FIG. 6, the illustrated machine includes a housing orbase which includes a bottom 111 and an upstanding cylindrical portion112. Fitted within such cylindrical portion is a squeeze piston 1 13provided with piston rings seen at 114 and 115. Such squeeze pistonincludes an upstanding cylindrical portion 116 projecting slightly abovethe top edge of the cylindrical portion 112 of the housing in thelowermost position of such squeeze piston.

A jolt table 120 includes a depending cylindrical extension 121 whichfits within the upstanding cylindrical portion 116 of the squeezepiston. Mounted within such depending cylindrical extension 121 of thetable 120 is ram 122. A ram follower 123 of reduced diameter is providedsubjacent the underside of the ram 122. Such ram follower need not bephysically connected to the ram. The ram is provided with a dependingannular skirt 124 making the ram substantially coextensive with thecylindrical extension 121 of the table 120 in the FIG. 5 position.

The ram follower projects downwardly through annular boss 126 in thesqueeze piston 113, the top of which is provided with packing retainer127 secured thereto by fasteners 128. A piston ring 129 is provided insuch retainer riding against the ram follower 123.

The table 120 is provided with one or more downwardly projecting guidepins 130 projecting through bushings 131 in bosses 132 projecting fromthe housing 110. The lower ends of such guide pins are provided withstop nuts indicated at 133 which limit the upward movement of the table120 with respect to the housing 110. in this embodiment, the maximumstroke of the table may, for example, be approximately 7-% inches. This,of course, may vary depending upon the type and size of machine withwhich the present invention is employed.

The table 120 supports pattern plate on which is provided pattern 141.The pattern plate in turn supports flask 142 which is filled withmolding sand 143 from an overhead hopper, not shown. To fill the moldbox formed by the flask and pattern plate with the sand 143, squeezehead 144 is moved out of the way, such squeeze head being mounted onhead 145 cantilevered over the mold box from upstanding frame 146 in theback ofthe machine, as in the FIG. 1 embodiment.

The ram is provided with a plurality of lubrication passages indicatedat 150 and lubrication passages 151 are also provided through thecylindrical portion 112 of the housing 110. The chamber 152 between theram and the top of the piston 113 is connected to atmosphere throughpassages 153. Such passages terminate on the underside of the table 120as indicated at 154 with the horizontal branches being closed by plugs155.

The chamber between the top of the ram and the underside of the tablecan be pressurized through jolt air passage 161. Exhaust ports 162 areprovided in the depending cylindrical extension 121 of the table 120 andcommunicate with vertical passages 163 in such extension which in turncommunicate with passages 164 in the cylindrical extension 116 of thesqueeze piston 113. The ram 122 is provided with a teflon or likematerial piston ring as indicated at 165 adjacent the top edge thereof.Passage 166 is provided in the housing 110 communicating with squeezechamber 167 beneath squeeze piston 113, such chamber including recess168 extending beneath ram follower 123 in the position shown in FIG. 1.

The description of the operation now follows. With the flask 142positioned on the pattern plate 140 on the table 120 and filled withsand 143, to obtain conventional or anvil jolt. air at plant or linepressure (about 80 psi.) enters the jolt cavity 160 above ram 122through passage 161. The pressure in chamber 160 lifts table 120 untilexhaust ports 162 are opened. The jolt air pressure now exhausts throughthe passages 162, 163 and 164 exhausting adjacent the top of thecylindrical extension 116 of the piston 113. On exhaust, the jolt tabledrops and strikes the top annular surface of the extension 116 ofsqueeze piston 113 as indicated at 170. The squeeze piston 113 is duringthe anvil or conventional jolt bottomed in the housing as shown at 171in FIG. 1. The ram 122 is also bottomed in such housing through follower123 and the downward force on the ram resulting from the pressure injolt chamber 160 is accepted through the ram 122 and the follower 123which is in contact with the housing bottom 11. This anvil jolt may berepeated as desired.

To obtain the strike on the top of the cylindrical extension 116 of thesqueeze piston 113 as seen at 170, there is provided a slight clearanceseen at 172 between the top of the ram 122 and the underside of thetable 120. If desired, the dimension of the follower and ram may beslightly extended to obtain during the anvil jolt a strike at theopposed surfaces indicated by such clearance.

Now referring to H0. 6, during squeeze air under pressure is admitted tothe squeeze chamber 167 through port 166 and the squeeze piston 113moves upwardly carrying with it the table 120. The squeeze head 144telescopes within the top of the flask pressing the sand against thepattern. The ram 122 also moves upwardly and is held in contact with theunderside of the jolt table as indicated at 173 by the squeeze pressureacting on the bottom surface 174 of the ram follower 123 which isexposed to the squeeze pressure in the squeeze chamber 167 beneath thepiston 113.

Jolt during squeeze is obtained by introducing line pressure (80 p.s.i.)through jolt line 161 into jolt chamber 160. This pushes ram 122downwardly until air exhausts through exhaust passages 162, 163 and 164exiting at the top of the cylindrical extension 116 of the squeezepiston 113. When exhaust occurs the squeeze pressure in chamber 167acting on the underside 174 of the ram follower 123 causes the ram tomove upwardly striking the underside of the jolt table at 173. As in theFIG. 4 embodiment, the ram is also assisted by pressure in chamber 152even though such chamber is vented. Such shockless jolt during squeezemay continue until the mold has obtained its desired maximum overallhardness.

It is noted that as the jolt pressure in the chamber 160 drives the ram122 and follower 123 downwardly, the latter projects into the squeezechamber 167 accordingly reducing its volume and increasing slightly thesqueeze pressure. As the follower is driven out of the chamber 167 bythe pressure therein, the squeeze pressure is reduced. The squeezepressure thus pulsates or varies with the shockless jolt strikeoccurring at the dip or minimum pressure in such pulsations. Maximumsqueeze pressure is obtained between jolt strikes. The slight reductionin squeeze pressure during the jolt strike is believed to permit thesand to move better obtaining more compactness and thus obtaining thedesired maximum overall hardness of the mold.

The volume of the cavities 160 and 167 as well as the weights of themoving parts again must be carefully determined to obtain the desiredaction.

After the mold is rammed, the table is lowered and the pattern 141 isdrawn from the mold.

I, therefore, particularly point out and distinctly claim as myinvention:

1. A foundry molding machine having a squeeze table, and a squeezepiston supporting said table, wherein the improvement comprises a ramextending through said piston to enable both anvil or shockless jolt,said ram floating on the squeeze pressure to obtain shockless joltduring squeeze.

2. A foundry molding machine as set forth in claim 1 including acylindrical extension on said piston of said assembly and a cylindricalextension on said table, said table extension being telescoped into saidpiston extension.

3. A foundry molding machine as set forth in claim 2 wherein said tableextension and the upper end of said ram form a jolt cavity, the end ofsaid ram exposed to such cavity being larger in area than the endexposed to such squeeze pressure.

4. A foundry molding machine as set forth in claim 3 including anexhaust port in said table extension operative to vent such cavity aspressure therein relatively moves said ram and table.

5. A foundry molding machine as set forth in claim 4 including a secondcavity formed by said ram and piston-cylinder assembly between saidfirst cavity and said piston, and means operative to maintain saidsecond cavity vented.

6. A foundry molding machine as set forth in claim 5 wherein said tableextension extends into said second cavity, said last mentioned meansbeing a vent passage in said table extension.

7. A foundry molding machine as set forth in claim 1 including acylindrical extension on said table, said ram being mounted forreciprocation in said table extension.

8. A foundry molding machine as set forth in claim 7 wherein said ramincludes a cylindrical extension of reduced diameter projecting throughsaid piston.

9. A foundry molding machine as set forth in claim 8 including anextension on said piston supporting said table in one position thereof,said ram and its extension being bottomed on the cylinder of saidpiston-cylinder assembly and slightly clearing said table whereby airpressure between said ram and table will elevate the latter to drop thesame on said piston extension when said pressure is vented to obtain ananvil jolt.

10. A foundry molding machine as set forth in claim 1 wherein said ramis bottomed on said cylinder of said pistoncylinder assembly and clearssaid table in the lowermost position thereof, whereby air pressurebetween said ram and table will elevate said table and drop the same onventing of such pressure to obtain an anvil jolt.

11. A foundry molding machine as set forth in claim 1 including a pairof arms operative to swing adjacent said table to facilitate lifting ofa mold box therefrom.

12. A foundry molding machine having an upstanding cylindrical housing,a table adapted to support a sand filled flask, and a piston in saidhousing supporting said table for vertical movement, the improvementcomprising a jolt ram cooperating with said table and extending throughsaid piston to enable both anvil or shockless jolt, said ram beingexposed to the pressure beneath said piston.

13. A foundry molding machine as set forth in claim 12 including acylindrical extension on said piston thus supporting said table.

14. A foundry molding machine as set forth in claim 13 including acylindrical extension on said table telescoping over said ram andforming therewith a jolt cavity on top of said ram.

15. A foundry molding machine as set forth in claim 14 wherein both saidpiston and said ram are bottomed on said housing when there is nopressure beneath said piston whereby pressurization and venting of suchcavity will elevate said table and then drop the same to provide ananvil jolt.

16. A foundry molding machine as set forth in claim 15 wherein said ramclears said table when bottomed on said housing so that said tablestrikes the top annular edge of the cylindrical extension on said pistonto provide such anvil jolt.

17. A foundry molding machine as set forth in claim 16 wherein said ramincludes an extension of reduced diameter extending through said piston.

18. A foundry molding machine as set forth in claim 12 including a pairof pivotally mounted arms adapted to lift such sand filled flask fromsaid table to facilitate inversion.

19. A jolt-squeeze molding machine capable of producing an anvil orshockless jolt comprising a squeeze piston, jolt means, a table, saidsqueeze piston supporting said table for movement toward and away from asqueeze head, said jolt means comprising a ram operative to strike saidtable, said ram including an extension projecting through said squeezepiston and into the pressure side chamber of said piston.

20. A jolt-squeeze molding machine as set forth in claim 19 including acylindrical extension on said piston supporting said table, and ahousing in which said piston is mounted for movement.

21. A molding machine as set forth in claim 20 wherein both said squeezepiston and said ram are bottomed on said housing in the lowermostposition of said table.

22. A molding machine as set forth in claim 21 including a cylindricalextension on said table cooperating with said jolt ram to form a joltcavity above said ram, and means to pressurize said cavity to elevatesaid table and vent said cavity to drop said table to obtain an anviljolt.

23. A jolt-squeeze molding machine comprising a frame, a verticallymovable table in said frame adapted to support a sand filled mold box,an overhead squeeze head, a jolt mechanism in said table capable ofjolting the sand in such mold box prior to and during elevation of thelatter against said head, a pair of arms operative to lift such mold boxfrom said table to facilitate inversion, said jolt mechanism includingmeans to provide an anvil jolt prior to elevation and a shockless joltduring elevation.

24. A jolt-squeeze molding machine as set forth in claim 23 wherein saidjolt mechanism includes a ram stationary for said anvil jolt and movablefor said shockless jolt.

25 A jolt-squeeze molding machine as set forth in claim 24 including anexpansible squeeze pressure chamber operative to elevate said table,said ram floating on said squeeze pressure therein during shocklessjolt.

i IF i i

1. A foundry molding machine having a squeeze table, and a squeezepiston supporting said table, wherein the improvement comprises a ramextending through said piston to enable both anvil or shockless jolt,said ram floating on the squeeze pressure to obtain shockless joltduring squeeze.
 2. A foundry molding machine as set forth in claim 1including a cylindrical extension on said piston of said assembly and acylindrical extension on said table, said table extension beingtelescoped into said piston extension.
 3. A foundry molding machine asset forth in claim 2 wherein said table extension and the upper end ofsaid ram form a jolt cavity, the end of said ram exposed to such cavitybeing larger in area than the end exposed to such squeeze pressure.
 4. Afoundry molding machine as set forth in claim 3 including an exhaustport in said table extension operative to vent such cavity as pressuretherein relatively moves said ram and table.
 5. A foundry moldingmachine as set forth in claim 4 including a second cavity formed by saidram and piston-cylinder assembly between said first cavity and saidpiston, and means operative to maintain said second cavity vented.
 6. Afoundry molding machine as set forth in claim 5 wherein said tableextension extends into said second cavity, said last mentioned meansbeing a vent passage in said table extension.
 7. A foundry moldingmachine as set forth in claim 1 including a cylindrical extension onsaid table, said ram being mounted for reciprocation in said tableextension.
 8. A foundry molding machine as set forth in claim 7 whereinsaid ram includes a cylindrical extension of reduced diameter projectingthrough said piston.
 9. A foundry molding machine as set forth in claim8 including an extension on said piston supporting said table in oneposition thereof, said ram and its extension being bottomed on thecylinder of said piston-cylinder assembly and slightly clearing saidtable whereby air pressure between said ram and table will elevate thelatter to drop the same on said piston extension when said pressure isvented to obtain an anvil jolt.
 10. A foundry molding machine as setforth in claim 1 wherein said ram is bottomed on said cylinder of saidpiston-cylinder assembly and clears said table in the lowermost positionthereof, whereby air pressure between said ram and table will elevatesaid table and drop the same on venting of such pressure to obtain ananvil jolt.
 11. A foundry molding machine as set forth in claim 1including a pair of arms operative to swing adjacent said table tofacilitate lifting of a mold box therefrom.
 12. A foundry moldingmachine having an upstanding cylindrical housing, a table adapted tosupport a sand filled flask, and a piston in said housing supportingsaid table for vertical movement, the improvement comprising a jolt ramcooperating with said table and extending through said piston to enableboth anvil or shockless jolt, said ram being exposed to the pressurebeneath said piston.
 13. A foundry molding machine as set forth in claiM12 including a cylindrical extension on said piston thus supporting saidtable.
 14. A foundry molding machine as set forth in claim 13 includinga cylindrical extension on said table telescoping over said ram andforming therewith a jolt cavity on top of said ram.
 15. A foundrymolding machine as set forth in claim 14 wherein both said piston andsaid ram are bottomed on said housing when there is no pressure beneathsaid piston whereby pressurization and venting of such cavity willelevate said table and then drop the same to provide an anvil jolt. 16.A foundry molding machine as set forth in claim 15 wherein said ramclears said table when bottomed on said housing so that said tablestrikes the top annular edge of the cylindrical extension on said pistonto provide such anvil jolt.
 17. A foundry molding machine as set forthin claim 16 wherein said ram includes an extension of reduced diameterextending through said piston.
 18. A foundry molding machine as setforth in claim 12 including a pair of pivotally mounted arms adapted tolift such sand filled flask from said table to facilitate inversion. 19.A jolt-squeeze molding machine capable of producing an anvil orshockless jolt comprising a squeeze piston, jolt means, a table, saidsqueeze piston supporting said table for movement toward and away from asqueeze head, said jolt means comprising a ram operative to strike saidtable, said ram including an extension projecting through said squeezepiston and into the pressure side chamber of said piston.
 20. Ajolt-squeeze molding machine as set forth in claim 19 including acylindrical extension on said piston supporting said table, and ahousing in which said piston is mounted for movement.
 21. A moldingmachine as set forth in claim 20 wherein both said squeeze piston andsaid ram are bottomed on said housing in the lowermost position of saidtable.
 22. A molding machine as set forth in claim 21 including acylindrical extension on said table cooperating with said jolt ram toform a jolt cavity above said ram, and means to pressurize said cavityto elevate said table and vent said cavity to drop said table to obtainan anvil jolt.
 23. A jolt-squeeze molding machine comprising a frame, avertically movable table in said frame adapted to support a sand filledmold box, an overhead squeeze head, a jolt mechanism in said tablecapable of jolting the sand in such mold box prior to and duringelevation of the latter against said head, a pair of arms operative tolift such mold box from said table to facilitate inversion, said joltmechanism including means to provide an anvil jolt prior to elevationand a shockless jolt during elevation.
 24. A jolt-squeeze moldingmachine as set forth in claim 23 wherein said jolt mechanism includes aram stationary for said anvil jolt and movable for said shockless jolt.25. A jolt-squeeze molding machine as set forth in claim 24 including anexpansible squeeze pressure chamber operative to elevate said table,said ram floating on said squeeze pressure therein during shocklessjolt.